Digital maps are displayed and are used in a wide variety of devices, including car navigation systems, hand-held GPS units, mobile phones, and many websites. Moreover, digital maps may contain a wealth of map information such as satellite images, roads, street photographs taken from the ground level, specific information for a business, etc. However, the physical size and display resolution limitations of many device display screens restrict the amount of map information that may be displayed to a user at one time. Moreover, a desired viewing resolution or viewing magnification of a displayed digital map may limit a user to viewing only a small portion of the map at one time. As a result, some map features and information may not be contained in the current viewing window or viewport of the map at a user-selected level of detail or magnification or with a particular resolution or a size of a display screen.
To cope with map information that is not contained within the viewport or with content that is “off-screen,” existing map systems have placed overlays or indicators that indicate a direction pointing toward the off-screen content. These existing map systems have generally placed overlays at the edge of the viewport or next to a search box to suggest a general direction in which the off-screen content is located with respect to the displayed map content. Other current map systems have implemented radar-like or sonar-like “pings” that generate a series of ever-expanding circles that originate from the location of the off-screen content and subsequently appear on the displayed portion of the map to a user. In these map systems, a user can deduce, from the size and the arc of the expanding circle or ping, the direction of and approximate distance to the location of the off-screen content. However, these overlay indicators of existing map systems generally occlude or obstruct the displayed portion of the map and conceal map information that is positioned directly underneath a placed overlay indicator. Moreover, the overlay indicators may further clutter an already information-dense displayed portion of the map and may confuse the user in providing additional information.